The disclosure relates to three-dimensional semiconductor memory devices, and more particularly, to three-dimensional semiconductor memory devices having enhanced integration.
Attempts are being made to increase the integration of semiconductor devices. As the integration of the semiconductor devices is an important factor in determining product price, high integration is increasingly demanded in particular. The integration of a two-dimensional or planar semiconductor device is primarily based on the area occupied by its unit memory cell, and consequently the size of fine patterns is a factor. However, extremely expensive processing equipment is needed to produce fine patterns, which sets a practical limitation on increasing the integration of two-dimensional or planar semiconductor device. Therefore, there have been proposed three-dimensional semiconductor memory devices having three-dimensionally arranged memory cells.